List of top Physics Questions

The radius of the path of a charged particle of mass \( m \) and charge \( q \) moving with a speed \( v \) in a magnetic field \( B \) is given by:

Two capacitors of capacities 10 µF and 20 µF are connected in series across a 200 V source. The charged capacitors are disconnected from the source and reconnected in parallel with their positive plates together. The potential difference across each capacitor is:

The resultant amplitude of superposition of two waves \( y_1 = a \cos(\omega t) \) and \( y_2 = a \cos(\omega t + \phi) \) is:

The charge flowing through a resistance \( R \) varies with time as \( q = at - bt^2 \), where \( a, b \) are positive constants. The total heat produced in \( R \) is:

A magnetic field of 1 T is acting on a wire carrying a current of 1 A so that the wire is at rest in air. If the mass of the wire is 100 g, then the length of the wire is:

A particle of charge \( q \) is shot with speed \( V \) towards another fixed particle of charge \( Q \). It reaches the closest distance \( r \) and then returns. If \( q \) were shot with speed \( 2V \), then the closest distance of approach of \( Q \) is:

If the temperature of a gas is increased from 27°C to 927°C, the rms speed is:

Two identical balls \( P \) and \( Q \) are moving with the same velocity. If the velocity of \( Q \) is reduced to zero and that of \( P \) is reduced to half, the ratio of change in temperatures of \( P \) to \( Q \) is:

The external work done when air expands from 10 litres to 15 litres at a pressure of 2 atm is:

A thin oil layer floats on water. A ray of light making an angle of incidence \( 45^\circ \) shines on the oil layer. The angle of refraction of light ray in water is:

The superposition takes place between two waves of frequency \( f \) and amplitude \( a \). The resultant intensity is directly proportional to:

A simple pendulum is suspended in a car moving on a circular track of radius \( R \) with a uniform speed of \( \sqrt{1.732 g R} \). The pendulum is making small oscillations in a radial direction about its equilibrium position with a time period \( T \). If the car is at rest, the time period of the pendulum is:

The bulk modulus \( B \) and compressibility \( k \) are related by:

According to Newton's law of cooling, the temperature of a body is \( T \) at time \( t \) and the temperature of the surroundings is \( T_s \). The rate of change of temperature is given by \[ \frac{dT}{dt} = k(T_s - T) \] If the initial temperature at time \( t = 0 \) is \( T_0 \), then the temperature \( T \) is:

A fluid flows through a pipe of diameter 5 cm with a velocity 2 m/s. If the pipe is constricted to a diameter of 3 cm, the velocity of fluid at the constriction is:

A car is moving with a speed of 5 m/s on a circular road having radius of curvature 10 m and coefficient of friction 0.5. For the safe journey of the car, the banking angle of the road should be:

The time taken by a net force of 10 N to change the velocity by 4 m/s of a body of mass 10 kg is:

An electron moving along positive x-direction with velocity \( 2 \times 10^5 \) ms\(^{-1}\) enters a magnetic field of \( \vec{B} = \hat{i} + 4 \hat{j} + 3 \hat{k} \) T. The magnitude of the force acting on the electron is:

The work done in lifting a body of mass 2 kg from the surface of the earth to a height 10 m is:

A point \(P\) on the wheel of radius \(R\) is initially in contact with the ground. When the wheel rolls forward half a revolution, the displacement of the point \(P\) is:

A girl of mass 30 kg stands at one end of a plank of mass 120 kg and length 4 m. Initially the plank lies at rest on a horizontal frictionless surface. If the girl walks to the other end of the plank, the distance that the girl moves relative to the ground is:

The most accurate measurement among the following is:

The driver of a train moving with speed \(V_1\), observes a train moving at distance \(d\) ahead on the same track slowly in the same direction with a speed \(V_2\). The driver applies breaks to give his train a constant retardation \(a\). If there was no collision between the trains, then

A steel ball of radius 0.05 cm and density \( 7.8 \, \text{g/cm}^3 \) is dropped into water. What is its terminal velocity?
(Density of water \( = 1 \, \text{g/cm}^3 \), Viscosity of water \( = 0.001 \, \text{Pas} \))